The grid-connected photovoltaic power generation technology has developed quickly in recent years, but it also poses risks such as the islanding effect. The realization of real-time monitoring of islanding effect is of significance for ensuring the stable operation of photovoltaic power generation systems. Therefore, aimed at the islanding fault of grid-connected photovoltaic power generation systems, a data-driven subspace-based islanding detection scheme is proposed. First, the fundamental wave from the voltage signal and the secondary harmonic signal of voltage at the point of common coupling are taken as the basis for islanding detection, and a voltage fundamental wave output predictor based on the subspace identification approach is designed. An adaptive filter for islanding detection is designed to track the fundamental wave from the voltage signal in real time, and the fundamental wave from the voltage signal is amplified to generate a residual signal. On this basis, an islanding fault detector is designed according to the residual signal and the secondary harmonic signal of voltage, so as to judge whether the system suffers the islanding fault. Finally, the effectiveness of the proposed approach was verified by simulation results.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |